On Tue, Nov 22, 2011 at 01:14:51PM +0000, Peter Maydell wrote:
> On 22 November 2011 13:06, Jubi Taneja <jubitaneja@gmail.com> wrote:
> > I am using arch/arm/configs/vexpress_defconfig to configure and build Linux
> > Kernel 3.1.1
> > http://launchpad.net/linux-linaro/3.1/3.1-2011.11/+download/linux-linaro-3.1-2011.11-0.tar.bz2
> > and then if I booth the zImage crated on Linaro QEMU
> > http://launchpad.net/qemu-linaro/trunk/2011.10/+download/qemu-linaro-0.15.50-2011.10.tar.gz
> > ,it works properly.
>
> > But if i enable the LPAE support in the config file, the kernel builds and
> > when I boot the kernel image on QEMU, it just prints the output as :
> >
> > Uncompressing Linux... done, booting the kernel.
>
> Does your kernel boot OK on real hardware?
>
> (ie, is a kernel with LPAE support expected to boot on a CPU like the
> A9 which doesn't have LPAE?)

No, that will not work for the foreseeable future.  Building two
pagetable models into a single kernel would likely be highly
contraversial, given Linus' views about LPAE-type platforms and HIGHMEM.

Conversely, a kernel without LPAE turned on will work on A15 (provided
you enable the A15 CPU support in the kernel).  But naturally, you will
only see the log 4GB of physical address space.

Cheers
---Dave